Endocrinology Exam Questions

Correct Answer: A

Rationale: Phaeochromocytoma is a rare neuroendocrine tumor that usually originates from the adrenal glands and produces excess catecholamines. The characteristic symptoms of phaeochromocytoma include paroxysmal (sudden and severe) hypertension, fear of impending death (angor animi), and episodic symptoms like palpitations, headache, and diaphoresis. However, weight gain is not a typical manifestation associated with phaeochromocytoma. In fact, patients with this condition may experience unintentional weight loss due to the effects of excess catecholamines on metabolism and appetite suppression. Therefore, weight gain is not a significant feature observed in individuals with phaeochromocytoma.

Correct Answer: B

Rationale: Pseudohypoparathyroidism is a rare genetic disorder that mimics the symptoms of hypoparathyroidism, despite normal or elevated levels of parathyroid hormone (PTH). The condition is characterized by hypocalcemia, hyperphosphatemia, and normal or elevated PTH levels. However, it is not associated with a raised level of plasma PIH (Parathyroid Inhibiting Hormone). In pseudohypoparathyroidism, the body's tissues are resistant to the action of PTH, leading to impaired calcium regulation. Other common features of pseudohypoparathyroidism may include cataract formation, mental retardation, and reduced levels of plasma phosphate.

Correct Answer: D

Rationale: In dwarfism conditions, the upper body segment being greater than the lower body segment is a characteristic feature seen in Achondroplasia. This condition results in a disproportionately short stature with short limbs but a trunk of normal length.

Correct Answer: A

Rationale: Cirrhosis is not a potential cause of elevated LDL cholesterol levels. The liver plays a significant role in cholesterol metabolism, and liver disease like cirrhosis can actually lead to decreased levels of LDL cholesterol. Elevated LDL cholesterol levels can be caused by conditions such as hypothyroidism, nephrotic syndrome, or the use of certain medications like thiazide diuretics.

Correct Answer: D

Rationale: Aldosterone is a hormone produced in the zona glomerulosa of the adrenal cortex, not the zona fasciculata (Choice A is incorrect). Conn's syndrome, also known as primary hyperaldosteronism, is characterized by excess aldosterone secretion, not a deficiency (Choice B is incorrect). Aldosterone production is under the control of the renin-angiotensin-aldosterone system, which is stimulated by factors such as low blood pressure, low blood volume, and high potassium levels. Elevated potassium in the blood directly suppresses aldosterone production by the adrenal glands, serving as a negative feedback mechanism to maintain electrolyte balance (Choice D is correct). The synthesis of aldosterone also requires cholesterol as the precursor, rather than pregnenolone (Choice E is incorrect). Lastly, aldosterone production is regulated in part by ACTH (adrenocorticotropic hormone), as it can enhance the effects of